Technical Field
The present disclosure relates to a wind turbine rotor blade and to a wind turbine having such a rotor blade. The present disclosure moreover relates to a method for producing a wind turbine rotor blade.
Description of the Related Art
Wind turbines are known and the currently most common type of wind turbine is a so-called horizontal-axis wind turbine, usually having three rotor blades. The dimensions of such wind turbines are getting bigger and bigger, namely in particular they have a higher hub or axis height and a larger rotor diameter with a correspondingly larger generator and greater feed-in power. Larger rotor diameters mean larger rotor blades which need to be transported from where they are manufactured to the respective site of erection. In particular the need to transport such long rotor blades, which can now have lengths as great as approximately 60 meters, regularly makes it necessary to use multi-part rotor blades.
Such multi-part rotor blades, which have at least two parts in the longitudinal axis, are known. For example, a type E-126 ENERCON wind turbine uses a rotor blade with a steel part close to the hub and a GFRP part remote from the hub. The structure is shown, for example, in U.S. Pat. No. 8,192,170.
The use of multi-part rotor blades can make transport easier. There is furthermore a growing desire to construct rotor blades that are as light and thin as possible so as thereby to save costs, to be precise not only the costs of the blade but also the cost of the subsequent support structures of the wind turbine and also the cost of erecting the wind turbine. In this sense, rotor blades are today being increasingly optimized, wherein a particularly good aerodynamic design is of course also important and needs to be taken into account when constructing a rotor blade.
WO2013/083451 shows an alternative of an assembled rotor blade consisting of a part close to the hub and a part remote from the hub, both parts being made substantially of GFRP. This example shows a very efficient solution for connecting the two rotor blade parts. Multiple connecting bolts are arranged in a peripheral row in the rotor blade, can be accessed there and in particular tightened and even prevent fatigue by virtue of pretensioining. This solution provides a particularly strong peripheral region at the connecting point of the two rotor blade parts, in which this connecting and bolting together is carried out by means of the said bolts. This shown connecting region which receives the multiple bolts must correspondingly absorb the entire load of the outer blade part, i.e., the one close to the hub. Both the corresponding connecting region at the rotor blade part close to the hub and the corresponding connecting region at the part of the rotor blade remote from the hub in practice have to absorb these forces completely and reliably. The force or load which occurs on these connecting regions also has to be introduced correspondingly into the respective part, i.e., the part of the rotor blade which is close to the hub or remote from the hub, respectively. The loads which need to be introduced can be considerable, which can sometimes also affect durability and at least be a potential point of weakness. The German Patent and Trademark Office has conducted a search as part of the priority application for the present application and found the following prior art: US 2011/0293432 A1, WO 01/42647 A2, WO 2006/ 002 621 A1, WO 2006/ 056 584 A1.